Will this interfere with my front bumper or splitter if I have one installed?

The Spirit style profile sits just below the bumper line and is designed to integrate cleanly with the OEM fascia. If you have a separate splitter or undertray, verify clearance with those components before installation to ensure no overlap where the lip meets your bumper mounting points.

Does the carbon fiber need to be sealed or painted, or does the clear coat handle everything?

The protective clear coat provides UV resistance and handles day-to-day weather exposure. The weave finish is fully visible under the coat, so no additional paint or sealing is required unless you prefer a different aesthetic.

Will this add noticeable weight to the front end?

Real carbon fiber is significantly lighter than OEM plastic or composite bumper panels, so you're actually reducing unsprung mass at the front. This is one of the primary advantages of carbon construction for a lip that bolts to your existing bumper.